NEWS : TECH (NFPC)

Virus Used As Biological Pacemaker in Heart

George Dvorsk, iO9

 

Biological pacemakers have been created before, but this is the first time that a single gene was shown to directly convert the heart muscle cells to pacemaker cells. Credit: Tarhill Photos Inc./CORBIS

Our heartbeats are triggered by a steady stream of electrical signals, which cause our heart muscles to contract with a regular rhythm. For some people, however, the ‘pacemaker cells' responsible for generating these pulses can fail, resulting in an erratic heartbeat. Normally, this problem is addressed by surgery and the insertion of an electric pacemaker device.

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But as a recent breakthrough at Cedars-Sinai Heart Institute now shows, it may be possible to convert ordinary heart cells into genuine pacemaker cells -- and it can be done with a known gene and a modified virus.

There are fewer than 10,000 pacemaker cells in the heart (out of billions of other heart cells), an astoundingly small number considering how important they are to critical biological function.

Worse, as age and disease takes its toll on the heart, these cells, also referred to as SAN cells (as they are clustered in the sinoatrial node -- SAN -- of the heart's right upper chamber), start to degrade, which can result in a cardiac arrest.

Pacemakers certainly provide a viable solution to the problem, but they're clunky, they break easily, they often lead to infections and they're limited by their finite battery life.

But this new idea appears to offer a much more elegant solution.

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Researchers Nidhi Kapoor, Hee Cheol Cho, and their colleagues injected a genetically modified virus carrying the crucial Tbx18 gene into guinea pigs. This caused ordinary heart cells to transform into the SAN cells; once infected, the heart cells became smaller, thin, and tapered, thus acquiring the exact characteristics of the pacemaker cells.

Tbx18 is the gene that's responsible for pacemaker cell development during the embryonic stage of development. But in this context, the gene directly reprogrammed the pre-existing heart muscle cells (cardiomyocytes) to the SAN cells.

Of the seven guinea pigs treated, five eventually developed heartbeats that were being driven by their new biologically endowed pacemaker.

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Biological pacemakers have been created before, but this is the first time that a single gene was shown to directly convert the heart muscle cells to pacemaker cells. And in fact, the new cells -- redubbed iSAN cells (induced SAN cells) -- were indistinguishable from native pacemaker cells. Previous attempts resulted in cells that were not true pacemaker cells.

Moreover, by avoiding the use of embryonic stem cells to derive pacemaker cells, the researchers have reduced the risk of cancerous cells emerging.

Once safety and efficacy can be proven in humans, the therapy will likely involve a direct injection of the virus into the patient's heart, or through the creation of pacemaker cells in the lab for eventual transplantation.

Read the entire study online at Nature Biotechnology.

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Brain Cells Made from Urine: DNews Nugget

Brain Cells Made from Urine: Scientist have discovered an uncomplicated technique for turning cells discarded in urine into neurons. Other research typically uses embryonic stem cells, which can be coaxed to grow into just about any cell found in the body, including brain cells. But there are certain risks associated with embryonic stem cells, such as the development of tumors after transplant into a body.

Biologist Duanqing Pei and his colleagues at China's Guangzhou Institutes of Biomedicine and Health have shown that kidney epithelial cells in urine can be turned into pluripotent stem cells, which can grow into any cell in the body. The scientists reprogrammed the epithelial cells by inserting new genetic information into the them. Then they allowed the cells to grow. In about twelve days -- about half the time of other procedures -- the pluripotent cells grew into a rosette shape common to neural stem cells. Next, the scientists transplanted the cells into newborn rat brains. Remarkably, the cells did not form tumors and after four weeks had taken on the shape of neurons. via Nature

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Hagfish Slime Makes Super-Clothes

 

Threads of hagfish slime, which the animals secrete when aggravated, could be woven to produce a material with the strength of nylon or plastic. Credit: randon D. Cole/CORBIS

One of the world’s creepiest creatures may be the source of new kinds of petroleum-free plastics and super-strong fabrics, according to research by scientists in Canada studying the hagfish, a bottom-dwelling creature that hasn’t evolved for 300 million years and produces a sticky slime when threatened. The gooey material is actually a kind of protein that turns into choking strands of tough fibers when released into the water.

A research team at Canada’s University of Guelph managed to harvest the slime from the fish, dissolve it in liquid, and then reassemble its structure by spinning it like silk. It’s an important first step in being able to process the hagfish slime into a useable material, according to Atsuko Negishi, a research assistant and lead author on the paper in this week’s journal Biomacromolecules.

“We’re trying to understand how they make these threads and how we can learn from that to make protein-based fibers that have excellent mechanical properties,” Negishi said. “The first step is can we harvest the threads. It turns out that is doable.”

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Negishi has been working with the hagfish for about four years in the laboratory, trying to understand some of the physical and chemical properties of the slime. The fish produces a protein which it releases into the water from glands along the side of its snake-like body. This video by researchers in New Zealand document how the hagfish is able to repel 14 attacks by predators, including several kinds of sharks.

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Negishi says the slime can be difficult to handle and there are plenty of reasons why most people, and fishermen, avoid them.

“They’re not the prettiest fish, they have big whiskers, they don’t have eyes,” Negishi said. “They don’t smell particularly nice either. They are wet clammy and wiggly. But they you appreciate what they are capable of doing and you respect them.”

As for the slime itself, Negishi says it smells like dirty seawater and has the consistency of snot.

“It feels like mucous but a little bit more wet,” she said. “If you hold the slime up into the air, the water will drip out of that and what you have leftover is something that is threadlike.”

The threads are made of intermediate filament, a protein in the same family as bone and nails. The hagfish threads are 100 times smaller than a human hair and have given the creature an evolutionary advantage as a unique defense mechanism. Negishi works in the laboratory of professor Douglas Fudge, director of the comparative biomaterials laboratory at the University of Guelph. Fudge says he thinks the hagfish slime threads could be woven to produce a material with the strength of nylon or plastic.

“What we’d like to see is synthetic petroleum-based fibers replaced by more sustainable ones,” he said.

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Fudge says it isn’t likely that the slime will be harvested from hagfish in large quantities. A better idea would be to figure out a way to transplant the slime-making genes into bacteria which can be cultured on an industrial scale. Researchers have been doing something similar with the protein that makes spider silk.

The research in Fudge’s lab is promising, according to Markus Buehler, professor of civil and environmental engineering at the Massachusetts Institute of Technology, and expert in biological materials.

“It’s exciting to see that they have been able to go from studying the natural system to actually take it apart and reassemble them,” Buehler said. Still, obstacles remain. “Scaling it up to where you can make engineering products is still a way to go.”

Mice Sniff Out Landmines: DNews Nugget

Mice Sniff Out Landmines: About 70 countries have landscapes filled with hidden landmines. These unexploded bombs are difficult to detect and wreak havoc and death to residents. Currently, metal detectors, radar, magnetometers and sniffer dogs are used to search for them. Now researchers are proposing an inexpensive solution: genetically modified mice who are 500 times more sensitive than their natural counterparts to the smell of explosives from mines.

Molecular neurobiologist Charlotte D'Hulst of Hunter College in New York used genetic modification to give mice odor-sensing neurons with a TNT-detecting receptor. Upon encountering the overwhelming odor of explosives, a mouse would have a seizure, D'Hulst told Technology Review. "We can only hope that our mice will show a seizure behavior ... upon detecting landmines. We won't have to work with food rewards; we will probably use some radio signaling system. A chip implant may track, report, and record their behaviors." The researchers still need to test the mice in behavioral studies. via Technology Review

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Text Book Encoded In DNA

Imagine a future where the amount of data on tyhe Web could be saved to a thumb drive. A storage medium already exists that can hold this amount of information. It's call DNA. 

DNA typically stores biological information in cells that direct structures like proteins do their jobs. But scientists are investigating ways to get DNA to store other kinds of information. This week Harvard researchers reported in the journal Science that they encoded an entire book into DNA. Not only that, they read back the text.

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The experiment hints towards future data-storage devices with capacities that eclipse the computer chips and hard drives used today.

"A device the size of your thumb could store as much information as the whole Internet," Harvard University molecular geneticist George Church, the project's senior researcher, told the Wall Street Journal.

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Though I was hoping for a more literary selection, the team's DNA translation was Church's text on genomic engineering, "Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves." On second thought, that does sound like it has literary potential.

How'd they do it? Well, it all boils down to letters and numbers.

If you remember back to your middle school biology class, DNA is composed of two coiled strands consisting of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T).

Using the zeros-and-ones of computer language, the Harvard team began with the digital version of the book. On paper, they translated the zeros into the A or C of the DNA base pair. Likewise, they translated the ones into the G or T.

Then they created actual DNA -- nearly 55,000 short strands that all included the new coded sequence that contained portions of the text.

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In this viscous-liquid or solid-salt form, researchers said that a billion copies of the book could easily fit into a test tube and that they could last for centuries, provided with the right conditions.

"It shows that the vast increase in capacity to synthesize and sequence DNA can be applied to store significant amounts of data," said synthetic biologist Drew Endy at Stanford University, who wasn't involved in the project. "If you wanted to have your library encoded in DNA, you could probably do that now."

Having just moved halfway across the country, schlepping the burden of my bloated book collection, this doesn't sound like a bad idea. Especially now that I've traded in a sprawling home in the country for a small, city apartment.

via Wall Street Journal

Credit: E.M. Pasieka/Science Photo Library/Corbis

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Tech Tackles Wine Allergies

Some people are allergic to certain wines -- that nice Loire Valley red gives them a rash or headache, or that California Chardonnay makes them sneeze. The University of British Columbia's Wine Research Center might have found a way to solve this problem.

The team at UBC has modified two genes of a strain of yeast called Saccharomyces cerevisiae, which has been used in winemaking for decades (if not centuries). The yeast was modified to eliminate the need for a species of bacteria needed for the winemaking process. That bacteria produces chemicals that cause allergic reactions. About 30 percent of the population has some allergy to wine.

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Ordinarily winemakers use yeast to convert the sugar in the grape juice to alcohol. But wine isn't just made from juice; it also involves something called must, which is the skin and other stuff from the grapes that get crushed. After the yeast converts the first batch of sugars to alcohol, there's a secondary fermentation that happens, as bacteria in the mixture convert malic acid –- which has a harsh taste –- into lactic acid, which is smoother. In modern commercial winemaking the bacteria is added deliberately.

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Hennie van Vuuren, the Director of the Wine Research Centre at UBC, who led the research, told Discovery News that the bacteria can present a problem: sometimes they convert chemicals called histidines in the wine to histamines. Histamines are what give some people allergic reactions, if they are particularly sensitive to them. (It is not always the histamines that cause the problem; sulfites can as well, and there are people who are allergic to the alcohol itself).

Van Vuuren said his team took the gene from the malolactic bacteria that allow the malic acid -- which yeast usually ignores -- to cross the yeast cell membrane. They also added a bacterial gene that allows the yeast to digest the malic acid.

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The result is yeast that eliminates the need for malolactic bacteria and avoids producing chemicals that can cause reactions to the wine. Since the yeast is digesting the same chemicals that the introduced bacteria would, it doesn't affect the taste.

Van Vuuren noted that for the wine industry it would be a big boost to sales, since it would mean all those people who can't drink wine would be able to do so. He himself has a wine allergy but tended to limit his drinking to wines that have aged. "I really like wine, I couldn't have a meal without it," he said. In older wines the histamines are less of an issue, as they break down over time. But that limited his selection to rather expensive wine, or to ports and Madeiras. So Van Vuuren wanted to solve the problem of making wine allergen-free. It took several years to find the right genes, and find a way to insert them into the right yeast.

As to which wines will use this new yeast, he couldn't say, though he noted that it has been approved for use in Canada and the U.S. Van Vuuren is awaiting approval from the European Union, and at that point, he said the South African winemakers will adopt it as well.

Credit: Wikimedia Commons

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Smoking Vaccine Extinguishes Cravings

Gum, patches, inhalers and those pseudo electronic cigarettes...a smoker certainly isn't without options if he or she needs help quitting. But ask anyone trying to shake his habit and you're likely to hear this: Nothing satisfies the cravings more than the real thing.

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Bearing that in mind, researchers at Weill Cornell Medical College developed a vaccine that addresses the craving. The vaccine could prevent those who've yet to try cigarettes from ever lighting up.

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The vaccine makes the recipient's kidney pump out antibodies that sweep the bloodstream of nicotine, thus cutting off the addictive rush before it ever reaches the brain.

The research team used the genetic sequence of an engineered nicotine antibody and piggy-backed it onto an adeno-associated virus (AAV), a virus designed to be harmless. Also included was genetic information for the vaccine to go to liver cells called hepatocytes. Once inside the nucleus of the hepatocytes, the antibody's genetic sequence caused the cells to emit more antibodies that neutralized nicotine in the bloodstream.

So far the vaccine has only been tested on mice, but the results were promising. Studies showed that the vaccine continuously produced high levels of the antibody.

Ronald G. Crystal, the study's lead investigator, compared the vaccine to one of the most famous video games of all time.

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"As far as we can see, the best way to treat chronic nicotine addiction from smoking is to have these Pacman-like antibodies on patrol, clearing the blood as needed before nicotine can have any biological effect," he said in a Weill Cornell press release. "Our vaccine allows the body to make its own monoclonal antibodies against nicotine, and in that way, develop a workable immunity."

Crystal and his team plan to test the vaccine on rats and then primates before testing it on humans.

via Gizmag

Credit: Brand X Picture / Getty Images

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Yeast Gets a Magnetic Personality

Scientists at Harvard's Wyss Institute have genetically engineered an organism to sense magnetic fields, showing that it's possible to make organisms react to magnetism even when they normally don't. 

The work points to a lot of applications in medicine, industry and research. For example, cells sensitive to magnetic fields tend to align themselves in a single direction like tiny compass needles. That means one could move them in a specific direction to, say, build up tissue into a specific shape. The technique could be used to target therapeutic cells at diseases and would also be useful in magnetic resonance imaging.

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Some species of bacteria sense magnetism because they have tiny bits of iron or iron compounds inside them. But most plants and animals don't, and when their cells are exposed to iron, they try to stuff it away into tiny, hollow spaces called vacuoles. (Many animals, including humans, need iron to survive, but that iron is metabolized in very different ways).

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Researchers Pamela Silver and Keiji Nishida took ordinary yeast and grew it in a medium containing iron. The yeast cells took in the iron and stored it inside vacuoles. The scientists then put a magnet under the plate where the yeast was and saw the yeast was slightly magnetic.

Nishida added a protein called ferritin, which joins with iron and prevents it from becoming toxic. He also used genetic engineering to block the yeast's ability to produce a protein that's used to carry the iron into the cell’s vacuoles. That let the iron circulate freely throughout the yeast cell and made the cell sensitive enough that it would migrate toward an external magnet.

One interesting effect was that the genetically altered yeast stored iron in its mitochondria. The altered yeast was also about three times as magnetic as wild yeast, which was just given iron supplements.

The researchers found that other proteins in the yeast -- also found in other animals, including humans -- could be combined to amp up the magnetism. The existence of these proteins in other animals means that with a little genetic tweaking, other one-celled creatures that could become tiny, living bar magnets.

Photo: Yeast made sensitive to magnetism by altering how it reacts to iron. The arrows point to two of the larger concentrations of iron in a single yeast cell.

Credit: Harvard Medical School

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Sequence Your Genome for Under $1,000

Personal medicine is a little bit closer. Now you can sequence your genome for about $1,000 in just one day.

SCIENCE CHANNEL: DNA Quiz

Genome sequencing was once the realm of big institutions with loads of money, but a company called Ion Torrent is changing that. At the Consumer Electronics Show in Las Vegas, the company showed off its gene-sequencing device called the Ion Proton.

The machine itself isn’t cheap, coming in at about $149,000. The company sells another model, called the Ion Personal Genome Machine, which costs about $50,000. But the Proton has a lot more computing power and can sequence genes much faster than the less expensive model because it uses a lab-on-a-chip system -- a technology based on semiconductors.

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The computing power is key, however, as it allows the Ion Proton to sequence a person's entire genome for about the same price as some medical tests. To put it in perspective, the cost of an MRI without any insurance would run from $500 to 3,500.

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The Ion Proton can also sequence exons, the protein-encoding regions of the genome where most disease-causing mutations happen. This opens up a lot to both researchers and doctors.

Via Technology Review

Image: Ion Torrent

This article is part of our ongoing coverage of this year's Consumer Electronics Show. Find more CES articles here.

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Old Genes Make New, Giant-Headed Ants

Every animal carries a record of its past in its genes -- sometimes teeth show up in birds and vestigial limbs on snakes and whales. Ants are no exception. What if that potential could be tapped? And what brings it out?

That’s what a group of scientists at McGill University thought when they ran into a colony of ants on Long Island. A colony of ants known as Pheidole morrisi (more commonly called big-headed ants) had members we call soldiers with really outsized heads and bodies. These were called “super soldiers.”

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Pheidole, like many other ant species, are divided into castes, such as workers, queens and soldiers. Different foods are given to them when they are larvae, which triggers hormones that determine which caste the ant grows up to be.

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Super soldiers occur naturally in some species of Pheidole in the southwestern United States and Mexico. But those living in upstate New York aren’t supposed to have the big heads. Ants are a pretty diverse lot and there are more than 1,100 species within even the Pheidole genus. But only eight of them naturally produce the super soldiers.

Biology professor Ehab Abouheif and PhD student Rajee Rajakumar wondered if the genes that build super soldiers were present in the Long Island ants all along, but were just waiting for some environmental factor to bring them out. The scientists first went to Arizona and collected two other species of ant in the same genus, Pheidole rhea and Pheidole obtusospinosa, which both have a subclass of super soldiers. They then observed how those two species developed their super soliders.

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Next, the scientists gave the young Long Island ants juvenile hormones at certain specific points in their development. In the Pheidole morrisi they got the super-soldier ants, which showed that the potential was always there. It just needed something to bring it out. One interesting phenomenon was the super soldiers had wing buds, which their cousins from Arizona did not. Many ant species develop wings as part of their development and ants and wasps share a common ancestor. The procedure worked in three different species of Pheidole, even though all three were separated by thousands of miles and millions of years of evolution.

Previously, few biologists thought such ancestral traits were important. They were just leftovers like the stuff in your attic. This shows that when necessary, nature has a “tool kit” that it can use to create big morphological changes -- some of them new.

Via: McGill University

Image: Alexander Wild

 

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